Re: USB-audio strange problems

[Takashi Iwai <tiwai@suse.de>]

At Thu, 20 Mar 2008 12:16:37 +0100,
Pavel Machek wrote:
> 
> > At Wed, 19 Mar 2008 22:12:47 +0100,
> > Pavel Machek wrote:
> > > 
> > > Hi!
> > > 
> > > Ok, so it took me a year to get back to this bug. Oops.
> > 
> > Oh well, I don't remember what was the exactly problem...
> 
> Yes, sorry about that.
> 
> > > > Yep, let's fix it.  Just to make sure (ane debugging easy atm), could
> > > > you attach the following?
> > > > 
> > > > - content of /proc/asound/cards
> > > > - content of /proc/asound/card*/stream*
> > > > - the output of "lsusb -v"
> > > > - the generated file via "alsactl -f store somefile"
> > > > 
> > > > If I remember correctly, alsamixer at least doesn't break if you build
> > > > snd-usb-audio driver with IGNORE_CTL_ERR enabled, right?
> > > 
> > > I got the usb soundcard to work. I still have IGNORE_CTL_ERR enabled.
> > > 
> > > Problem was not mixer after all... somehow it expects me to play sound
> > > as 8-bit, and then I can play 16-bit mono and actually hear
> > > it. _Strange_.
> > > 
> > > So:
> > > 
> > > mplayer -ao alsa:device=hw=0 -af format=u8  KDE_Startup.wav
> > > mplayer -ao alsa:device=hw=0 -af format=s16le -af resample=48000  -af channels=1 KDE_Logout_1.ogg
> > > 
> > > ...plays both files. 
> > > 
> > > Forget about the first mplayer, and it will play nothing.
> > 
> > Dalls DS4201 has a known bug that it doesn't handle U8 format but only
> > S8 format.  The driver changes the supported format flags from U8 to
> > S8 when this USB ID is detected.  So you cannot play U8 format
> > natively.  (Still strange that it is accepted by mplayer.)
> 
> But problem is: I have to. Otherwise the second mplayer will produce
> just silence.

How about "-ao alsa:device=plughw=0 -af format=u8" ?

> Also, even with that treatment, I'm unable to play stereo :-(.

What shows stream* proc file while playing a 16bit stereo file?


Takashi